In network communication using a Session Initiation Protocol (SIP), such that a user agent is connected to a predetermined real SIP server and perform communication, it is required that information of a user agent should be registered in a real SIP server. Also, in order to register a user agent, a register method is used in SIP.
In this case, such that a user agent registers user agent information in at least one real SIP server using a register method, register message must be directly transmitted and received between the user agent and at least one real SIP server in which the information is to be registered. Also, in case that an authentication with respect to the user agent is required for registering user agent information, a real SIP server can register information of the user agent by a predetermined authentication between the user agent and the real SIP server.
Hereinafter, a process in which user agent information is registered in a real SIP server according to a conventional art will now be described.
FIG. 1 is a diagram illustrating a general process of registering user agent information in a single real SIP server not requiring authentication. A reference numeral 101 indicates a user agent, and a reference numeral 102 indicates a real SIP server.
A register process between a user agent and a real SIP server in SIP according to RFC3261 in association with SIP of a conventional art is like following.
A user agent 101 transmits a first register message 103 to a real SIP server 102.
The first register message may be composed of information such as indicated by a reference numeral 103. Since the information included in the SIP message is well-known to those skilled in the art, detailed description now be omitted.
The real SIP server 102 receiving the first register message 103 transmits an acknowledgement message 104 to the user agent 101. The acknowledgement message 104 may be 200 OK message widely used in general SIP.
The user agent 101 receives the acknowledgement message 104, and the process of registering in the real SIP server 102 is finished.
FIG. 2 is a diagram illustrating a general process of registering user agent information in at least one real SIP sever not requiring authentication.
Referring to FIG. 2, in operation 201, a user agent transmits a first register message to a first real SIP server. The first register message has the same form as the message form illustrated in FIG. 1.
In operation 202, the first real SIP server receives the first register message, registers information of the user agent, and transmits an acknowledgement message to the user agent.
In operation 203, the user agent receives the acknowledgement message and transmits a second register message to a second real SIP sever in which the information of the user agent is registered next.
In operation 204, the second real SIP server receives the second register message, registers the information of user agent, and transmits an acknowledgement message to the user agent.
The process described above is repeated until the information of the user agent is registered in the entire real SIP server in which the user agent is going to be registered. Accordingly, the user agent has to record information of the at least one real SIP server in which the user agent is going to be registered. In case that network address information of the real SIP server is not known, network addresses of the entire real SIP server connected to the user agent is obtained via broadcasting. Also, the entire real SIP server, register messages, and acknowledgement messages should be transmitted and received.
FIG. 3 is a diagram illustrating a general process of registering user agent information in single real SIP server requiring authentication.
According to RFC-3261 with respect to SIP, HTTP authentication method is recommended for authenticating users in a register process between a user agent and real SIP servers. A process of registering user agent information in a real SIP server according to the HTTP authentication method is like following.
In operation 301, a user agent transmits a first register message to an SIP server. In this case, the first register message may include information as following as an example.
REGISTER sip:192.168.1.150 SIP/2.0From: <sip:20001@192.168.1.150>;tag=7701a8c0-13c4-14-6dc6-76daTo: <sip:20001@192.168.1.150>Call-ID: 7701a8c0-13c4-14-6d06-5aef@192.168.1.119CSeq: 1 REGISTERVia: SIP/2.0/UDP 192.168.1.119:5060;branch=z9hG4bK-14-6dc8-370bMax-Forwards: 70Supported: 100rel,replacesContact: <sip:20001@192.168.1.119>Expires: 3600Content-Length:0
In operation 302, the real SIP server receives the first register message and transmits a first response message required for authentication to the user agent. In this case, 401 Unauthorized message can be used as the first response message, and the first response message may include information as following as an example.
SIP/2.0 401 UnauthorizedVia: SIP/2.0/UDP 192.168.1.119:5060;branch=z9hG4bK-14-6dc8-370bFrom: <sip:20001@192.168.1.150>;tag=7701a8c0-13c4-14-6dc6-76daTo: <sip:20001@192.168.1.150>;tag=atelo-5dd5-b05276c1Call-ID: 7701a8c0-13c4-14-6d06-5aef@192.168.1.119CSeq: 1 REGISTERContent-Length: 0WWW-Authenticate:  Digestnonce=“MDAxMDk5ODE4MzExOjExMzFiaFlIV05oL0d1MjYxYUd2UnZUUHc9PQ==”,realm=“sip.ne.jp”
The first response message as described above includes a WWW-Authenticate header with respect to authentication, and the WWW-Authenticate header may include digest nonce value. The digest nonce value is information included for authenticating the user agent.
In operation 303, the user agent receives the first response message, generates a first register response message in response to the first response message, and transmits the first register response message to the real SIP server. The first register response message may include information as following as an example.
REGISTER sip:192.168.1.150 SIP/2.0From: <sip:20001@192.168.1.150>;tag=7701a8c0-13c4-14-6dc6-76daTo: <sip:20001@192.168.1.150>Call-ID: 7701a8c0-13c4-14-6d06-5aef@192.168.1.119CSeq: 2 REGISTERVia: SIP/2.0/UDP 192.168.1.119:5060;branch=z9hG4bK-15-6e46-4801Max-Forwards: 70Supported: 100rel,replacesContact: <sip:20001@192.168.1.119>Expires: 3600Authorization: Digest username=“20001.test_directory”, realm=“sip.ne.jp”,nonce=“MDAxMDk5ODE4MzExOjExMzFiaFlIV05oL0d1MjYxYUd2UnZUUHc9PQ==”, uri=“sip:192.168.1.150”,response=“b220ce33181c630194027c6bd0508756”,algorithm=MD5Content-Length:0
The first register response message as described above may include a response value in an authorization header which is an authentication response header, in response to the digest nonce value of the WWW-Authenticate header included in the first response message. For example, the response value may be a value hashed based on the nonce value.
Namely, the user agent analyzes the digest nonce value included in the first register message received from the real SIP server for authentication, generates a response value in response to the digest nonce value, and transmits the response value in the first register response message to the real SIP server.
In operation 304, the real SIP server receives the first register response message, ascertains information included in the first register response message, particularly, the response value, and transmits an acknowledgement message to the user agent when the information included in the first register response message is suitable for authentication response information. The acknowledgement message may include information as following as an example.
SIP/2.0 200 OKVia: SIP/2.0/UDP 192.168.1.119:5060;branch=z9hG4bK-15-6e46-4801From: <sip:20001@192.168.1.150>;tag=7701a8c0-13c4-14-6dc6-76daTo: <sip:20001@192.168.1.150>;tag=atelo-6ad4-b0545f09Call-ID: 7701a8c0-13c4-14-6d06-5aef@192.168.1.119CSeq: 2 REGISTERContent-Length: 0Date: 07 Nov 2004 09:05:12 GMTContact: sip:20001@192.168.1.119;expires=3600
In case that the information included in the received first register response message is not suitable for the authentication response information, the first response message is transmitted to the user agent in order to reattempt authentication.
FIG. 4 is a diagram illustrating a general process of registering user agent information in at least one real SIP server requiring authentication.
In conventional arts, such that a user agent registers user agent information in at least one real SIP server requiring authentication, processes with respect to the real SIP servers should be performed respectively.
In operation 401, the user agent transmits a first register message to a first real SIP server.
In operation 402, the first real SIP server receives the first register message and transmits a first response message to the user agent. As described referring to FIG. 3, the first response message may include a digest nonce value in a WWW-Authenticate header. For example, the first response message may include “1111” as the digest nonce value.
In operation 403, the user agent receives the first response message and transmits a first register response message to the first real SIP server in response to the first response message.
As described referring to FIG. 3, the first register response message can include a response value in an authorization header in response to the digest nonce value of the WWW-Authenticate header included in the first response message. In the example, the first register response message may include “aaaa” as a response value in response to the “1111” which is the digest nonce value of the first response message.
In operation 404, the first real SIP server receives the first register response message, ascertains the response value in the authorization header, and transmits an authentication acknowledgement message to the user agent in case that authentication response information is suitable.
In the example, the first real SIP server ascertains the “aaaa” included in the first register response message and transmits the authentication acknowledgement message to the user agent in case that authentication response information is suitable.
In case that the information included in the received first register response message is not the authentication response information, the first response message is transmitted to the user agent again in order to reattempt authentication.
The process as described above is identically applied to an information register process between the user agent and a second real SIP server.
Hence, according to the conventional art as described above, a user agent transmits a register message and receives an acknowledgement message, thereby registering information in a real SIP server.
However, since register messages are transmitted to real SIP servers respectively and acknowledgement messages with respect to the respective register messages should be ascertained in order to register information in at least one real SIP server, the number of transmitted messages and received messages becomes enormous, thereby increasing information to be processed by a user agent.
In addition, in reality in which the number of real SIP servers connected to a user agent by SIP is increased as nowadays, when the user agent registers severally user agent information in particular real SIP servers, loads on network is increased. In addition, the HTTP authentication is recommended for user authentication in SIP standard RFC3261. In order to register user agent information in real SIP servers performing authentication using the HTTP authentication, register messages should be transmitted to the entire respective real SIP servers, response messages should be received from the entire respective real SIP servers, register messages in response to the respective response messages should be generated and transmitted, and acknowledgement messages in response to the register response messages should be received.
Accordingly, in order to register user agent information in at least one real SIP server performing authentication, the number of transmitted messages and received messages becomes enormous to increase the amount of information to be processed by a user agent, thereby generating overload on the user agent.
Also, according to a conventional art, since a user agent registers information in respective real SIP servers by transmitting register messages, addresses of the entire respective real SIP servers should be recorded and kept. Since each of user agents should know network address of real SIP servers, broadcasting should be performed on networks, thereby more increasing loads on networks.
Also, according to a conventional art, since a user agent transmits registers message to respective real SIP servers and registers information, a difference of time that information is registered in the respective real SIP servers can grow larger, thereby increasing difference of time that information of the user agent is synchronized with the respective real SIP servers. Therefore, a method and an apparatus for solving the problems as described above is largely required